Luton Crown Court heard that Mr Whitaker was dropping off his wife Doris, 76, who has poor mobility, outside a hairdresser's in Kempston, Bedfordshire, in May last year when the incident occurred.

PC Taylor and his colleague PC Mark Harrison felt Mr Whitaker's car was causing an obstruction because it was parked on double yellow lines on the edge of a roundabout. Taylor told the jury that PC Harrison asked Mr Whitaker if he could move his Vauxhall Vectra.

"Quite surprisingly, what came from the vehicle was, 'What are you doing parking there? Piss off!' " said PC Taylor. He said he then decided to give the pensioner a parking ticket but Mr Whitaker refused to give PC Harrison his name and address. "I heard Mr Whitaker say, 'You are a bastard and a little man' at least twice to PC Harrison.

"He said it in a raised, aggressive voice," said PC Taylor, who is married with one child.

PC Taylor said that when Mr Whitaker refused to give his name and address again he decided to arrest him and administered a caution. He said he feared that Mr Whitaker was about to drive off so he reached in and took the keys.

As he did this Mr Whitaker allegedly lunged forward as if to bite his arm. He then tried to bite his finger, PC Taylor told the court. He said he then drew back and sprayed Mr Whitaker twice in the face from a distance of about a yard. He then handcuffed him.

The pensioner was held in a police station for about nine hours. He was charged with using insulting language but that accusation was later withdrawn by the Crown Prosecution Service. He received hospital treatment for the damage to his eyes.

One witness said PC Taylor pulled Mr Whitaker from his car then forced him into the back of a police car.